Induction of apoptosis by pyrazolo[3,4-d]pyridazine derivative in lung cancer cells via disruption of Bcl-2/Bax expression balance

In the rapidly expanding era of cancer target therapy, regulators of apoptosis are emerging as attractive therapeutic targets. X-linked inhibitor of apoptosis (XIAP) is of specific interest owing to its characteristic overexpression in a wide variety of neoplasms, with a resultant survival advantage for tumor cells and treatment resistance. In this study, we examined three pyrazolo [3,4-d] pyridazine derivatives (PPDs) through molecular modeling and studied their modes of interaction with XIAP-BIR3 domain. PPD-1, which possessed the highest binding affinity with XIAP, was tested on A549 (lung cancer cell line); HCT-116 (colorectal carcinoma cell line); HEPG2 (liver carcinoma cell line), HFB4 (normal human skin melanocyte cell line) and WI-38 (human embryonic lung fibroblasts). In comparison to cisplatin as a positive control, PPD-1 yielded remarkable cytotoxicity on all cancer cell lines, with the highest anti-tumor activity on A549 and a favorable therapeutic ratio. Flow cytometry studies concluded that PPD-1 treatment induces Sub G1 and G2/M cell cycle arrest and apoptosis. The percentage of apoptotic cells in PPD-1 treated A549 cells was considerably higher than that in untreated cells (10.06% vs 0.57%, respectively). To further investigate the mechanism of induction of apoptosis by PPD-1, Real time-PCR was used to quantify the expression levels of key apoptotic regulators. Significant overexpression of the effector capsase-3, pro-apoptotic bax and tumor suppressor gene p53 were noted as compared to untreated cells (7.19 folds, 7.28 folds, and 5.08 folds, respectively). Moreover, PPD-1 inhibited the expression of the anti-apoptotic bcl-2 gene to 0.22 folds. These findings demonstrate that PPD-1 treatment disrupts the Bcl-2/BAX balance in lung cancer cell lines, leading to apoptosis induction possibly through intrinsic mitochondria-dependent pathway. These novel insights elucidate the mechanism of PPD-1 cytotoxicity in lung cancer cell lines and offer a promising therapeutic approach that needs further study.

Synthesis of Novel Indolizine, Pyrrolo[1,2-A] Quinoline, and 4,5-Dihydrothiophene Derivatives Via Nitrogen Ylides and their Antimicrobial Evaluation

Treatment of 2-(2-bromoacetyl)-3 H-benzo[ f]chromen-3-one with pyridine, quinoline, and 2-methylquinoline afforded the corresponding pyridinium, quinolinium and 2-methylquinolinium bromides. The latter salts underwent [3 + 2] 1,3-dipolar cycloaddition with some electron deficient acetylene and ethylene derivatives to give the corresponding indolizine and pyrrolo[1,2- a]quinoline derivatives. Moreover, 2-(2-bromoacetyl)-3 H-benzo[ f]chromen-3-one reacted with arylidene cyanothioacetamides to afford the corresponding 2-amino-4,5-dihydrothiophene-3-carbonitriles. The synthesised compounds were characterised based on their elemental analysis and spectral data. Antimicrobial activity of some of the synthesised compounds was evaluated.

1,3,4-Thiadiazoles of pharmacological interest: Recent trends in their synthesis via tandem 1,3-dipolar cycloaddition: Review

This review article presents a survey of the utility of a new synthetic strategy for 1,3,4-thiadiazole derivatives based on reactions of nitrilimines with various functionalized sulfur dipolarophiles which proceed via tandem in situ 1,3-dipolar cycloaddition and β-elimination of simple molecule from the initially formed cycloadduct. The biological activities of some of the compounds prepared by such a strategy are pointed out. Only the literature reports within the period from 2000 to mid 2012 are covered.